172 WILLIAM G. DIETZ, M.D. 



punctures rather superficial, subcoufluent, giving the appearance of being cor- 

 roded. Scute] distinct, scaly. Elytra two-fifths wider at base than the protho- 

 rax, and one-half longer than wide, sides nearly straight for one-half their 

 length, then broadly rounded to the apex, striae quite distinct, not concealed by 

 the scales, punctures remote, interstitial setae short, suberect. paler than the 

 scales, postocular lobes feeble. Thighs clavate, tibiae moderately stout, widened 

 at tip, terminal hooks rather small ; claws connate nearly to the middle. Length 

 2.5 mm. ; 0.10 inch. 



Hah. — Montana. 



A single male specimen in Dr. Horn's collection not unlikely 

 Desmoris sordidus Lee, but smaller, however, the posterior tibiae are 

 unguiculate, thorax more densely and finely punctured, without 

 smooth, dorsal line. The eyes are rather a little more widely sepa- 

 rated beneath than usual in the Smicronyx. 



SYSTERTHA n. gen. 



Based on a few species in which the eyes are contiguous beneath. 

 Beak feebly curved, robust in the male, more slender in the female. 

 Antennae inserted two-fifths from the apex in the male, a little before 

 the middle in the female. Prothorax narrowed anteriorly and 

 broadly constricted at the apex. Scutel distinct. Elytra elongate, 

 nearly twice as long as wide. Prosternum moderately long in front 

 of the coxse, broadly emarginate and without antecoxal ridges, 

 postocular lobes obsolete or feebly developed. 



The species are narrow, elongate insects, densely clothed with 

 large, broadly oval, imbricate scales and known from the Pacific 

 slope only. The three species known to me are readily distinguished 

 as follows : 



Prothorax not wider than long, elytral setae procumbent, scarcely visible. 



Tarsi slender, fourth joint projecting much more than the length of the pre- 

 ceding joint; claws connate at the base only iiiibricsttiis. 



Tarsi stout, fourth joint scarcely projecting the length of the preceding joint ; 



claws connate two-thirds their length lioriiii. 



Prothorax wider than long, elytra not much wider at base than the prothorax. 

 setae suberect, conspicuous wit'liliaini. 



S. imbricatus Casey. — Narrowly oblong, black, legs rufous to piceous, 

 densely clothed with large, broadly oval, overlapping scales, white or pale ochre- 

 ous on the underside, gray, intermixed in varying proportions with brown, above. 

 Beak in the male stout, robust, very feebly curved, about as long as head and 

 prothorax, densely scaly throughout with the basal tufts prominent, in the female 

 longer than head and prothorax, scaly toward the base, constriction deep; scrobes 

 not rapidly descending, upper margin visible in its whole extent. Antennae 

 moderate, inserted two-flfths from the apex ( '^ ), or a little before the middle 

 ( 9 ). second joint of funicle longer than the third, outer joints not much wider, 



